1. Field of the Invention
The present invention relates generally to a cutting tool, and more particularly to a utility knife.
2. Description of the Related Art
A conventional utility knife has a handle and a blade retractably disposed in the handle. The handle consisted of two casings detachably combined together so that the casings are disassembled while the knife needed to be replaced.
In the prior art, U.S. Pat. No. 5,303,469 and U.S. Pat. No. 5,875,551 disclosed a cap to secure two casings. The first patent taught the cap engaged with the casings at rear ends thereof, under such condition, the cap will be totally disassembled from the casings and that might cause the cap easy to be lost. The second patent taught a shaft slidably mounted on one of the casings and connecting a rear end thereof with the cap such that the cap can be drawn out and be turned an angle to make the casings can be disassembled. In this patent provided the cap not disassembled from the casing, but it provided a complex structure.
The primary objective of the present invention is to provide a utility knife, which has a simpler mechanism to assemble and disassemble two casings in an easier way.
According to the objective of the present invention, a utility knife comprises a handle having a first casing and a second casing, a blade holder slidably received in the handle, a blade mounted on the blade holder, means for driving the blade holder moving, and a lock device pivoted on the first casing of the handle to be turned between an unlock position and a lock position. The lock device has at least a rib projected from a diameter orientation thereof. The second casing has a through hole and a gap beside the through hole and communicated with the through hole whereby the second casing is secured with the first casing while the lock device runs through the through hole of the second casing and is turned to the lock position for the rib against the second casing and the second casing is disassembled from the first casing while the lock device is turned to the unlock position for the rib corresponding to the gap.